Introduction to Migraine

It is important to appreciate that patients, and doctors in general, use the term migraine rather loosely.

Migraine usually begins in people under the age of 40, and is more common in women.

Classic migraine headache is unilateral and associated with an aura but these features are only seen in 60% and 20% of migraine patients respectively.

The image on the right is a representation of the type of aura experienced by migraine sufferers. The commonest auras are visual, for example rings, flashes and blurring. Paresthesia is also a relatively common aura.

Pathophysiology

The exact pathophysiology is undetermined.

Until recently, it was thought to be caused by altered blood flow. However, it is now thought that these vascular changes are the result of the headache, not the cause.

Currently, the most probable hypothesis is that migraine is not a disorder of blood vessels, but one of brain function.

Establishing a diagnosis of migraine

To establish a diagnosis of migraine, the physician should use five screening criteria:

• Pulsating
• Duration 4-72 hours
• Unilateral
• Nausea
• Disabling

If three of these features are present, the likelihood ratio (LR) for migraine is 3.5. If four are present, the LR is 24.

The best predictors for migraine can be summarised as follows: POUNDing (Pulsating, Duration of 4-72 hOurs, Unilateral, Nausea, Disabling